67 failure to protect the scene of a crime properly can impair the investigation, since this is an essential element to enable it to be successful.277 192. In addition, international standards indicate that, with regard to the crime scene, the investigator must, at least, photograph the scene, any other physical evidence and the body as it was found and after it has been moved; collect and preserve any samples of blood, hair, fibers, threads or other evidence; examine the area for footprints or any other impressions of an evidentiary nature, and draw up a report detailing any observations at the scene, actions of investigators, and location of all the evidence recovered.278 One of the most delicate actions at the site of the discovery is the handling of the corpse; this must only be done in the presence of professionals who should examine and move it correctly, based on the condition of the body.279 Among other obligations, the Minnesota Protocol establishes that, when investigating the scene of a crime, the area around the body should be closed off, and only the investigators and their staff should be allowed entry into the area.280 Until this has been done, any contamination of the area should be avoided and it should be guarded permanently.281 The Minnesota Protocol also establishes that it is essential that “[l]aw enforcement personnel and other non-medical investigators should coordinate their efforts […] with those of medical personnel.”282 193. Furthermore, due diligence in a forensic investigation of a death requires maintaining the chain of custody of all forensic evidence. 283 This consists in keeping a precise record, supplemented when appropriate by photographs and other graphic elements, to document the background to the evidence as it passes through the hands of different investigators responsible for the case.284 194. Regarding autopsies, as the Court has indicated, their purpose is to collect, at least, information to identify the deceased, the time, date, cause and manner of death. They should observe certain basic formalities, such as recording the date, starting and finishing times, and place where they are performed, and also the name of the professional who performs them. In addition, it is necessary, inter alia, to photograph the body adequately; to radiograph the body before it is removed from its pouch or wrappings; X-rays should be repeated both before and after undressing the body and any injury documented. Any absence, looseness or damage to the teeth should be documented, as well as all dental work, and the genitalia carefully examined looking for signs of sexual assault (supra para. 188). The United Nations Manual indicates that, at the scene of the crime, autopsy protocols should note the position of the body and its condition, including whether it is warm or cool, flexible or rigid; protect the deceased’s hands; note the ambient temperature, and collect 277 Cf. Case of Myrna Mack Chang v. Guatemala. Merits, reparations and costs. Judgment of November 25, 2003. Series C No. 101, para. 166, and Case of Luna López, supra, para. 164. 278 Cf. United Nations Model Protocol for a Legal Investigation of Extra-legal, Arbitrary and Summary Executions (Minnesota Protocol), supra, and Case of González et al. (“Cotton Field”), supra, para. 301. 279 Office of the United Nations High Commission for Human Rights. Modelo de protocolo latinoamericano de investigación de las muertes violentas de mujeres por razones de género, MEX/00/AH/10, p. 58. 280 Cf. United Nations Model Protocol for a Legal Investigation of Extra-legal, Arbitrary and Summary Executions (Minnesota Protocol), supra, and Case of González et al. (“Cotton Field”), supra, para. 301. 281 Cf. United Nations Model Protocol for a Legal Investigation of Extra-legal, Arbitrary and Summary Executions (Minnesota Protocol), supra, and Office of the United Nations High Commission for Human Rights. Modelo de protocolo latinoamericano de investigación de las muertes violentas de mujeres por razones de género, supra. 282 Cf. United Nations Model Protocol for a Legal Investigation of Extra-legal, Arbitrary and Summary Executions (Minnesota Protocol), supra. 283 Cf. United Nations Model Protocol for a Legal Investigation of Extra-legal, Arbitrary and Summary Executions (Minnesota Protocol), supra, and Case of González et al. (“Cotton Field”), supra, para. 305. 284 Cf. Case of González et al. (“Cotton Field”), supra, para. 305.